There are good edible huts out there here a link to one I used. Cut out the bottom or they will pee in it on the bottom and ruin it!
Oxbow Hay Company Timothy Club Cage Accessories at Drs. Foster and Smith
Ifyou dont like that one do a search for "Timotht hay hut" and you will find one you like.I did find one that was made bottomless at my local feed store!Plastic is bad especially if its from foriegn countries it may contain lead!